Renewable power sources that use renewable energy such as solar power and wind power to generate power are receiving attention, and the incorporation of renewable power sources into a power and is being promoted.
The output of a renewable power source depends on weather factors such as sunlight and the amount of wind. As a result, the output of a renewable power source is unstable, and as a consequence, when most renewable power sources are incorporated in a power grid, it is thought that the amount of power that can be supplied will become unstable, and the balance between supply and demand deteriorates.
As a method of adjusting the balance between power supply and demand in a power grid, a method is principally used in which power companies (the power generating side) adjust the output of thermal generators of a thermal generation power plant.
However, the method of adjusting the output of thermal generators to compensate the balance between power supply and demand that arises from the fluctuation in the output of renewable power sources is considered problematic and inadequate when the output of most renewable power sources fluctuates due to the effect of weather. As a result, a new scheme of adjusting the balance between power supply and demand that includes power consumers the consuming side) is now believed to be necessary.
As an example of this scheme, Patent Document 1 discloses a power management device that manages the balance between supply and demand of electric power by issuing to power consumers people) demands that prompt adjustment of the amount of power demand. This power management device adjusts the amount of power demand by causing power consumers to control electrical equipment according to demand.
As disclosed in Patent Document 1, a method of using demand to cause power consumers to adjust the amount of electric power demand is generally called demand-response. Demand response is hereinbelow referred to as “DR.” The FERC (Federal Energy Regulation Commission) defines DR as “Changes in electric usage by demand-side resources (from their normal consumption patterns) in response to changes in the price of electricity over time, or to incentive payments designed to induce lower electricity use at times of high wholesale market prices or when system reliability is jeopardized.”